Operators of telecommunication networks seek to utilize network resources (e.g., base stations associated with cells) in the best possible way to maximize user experience. Due to fluctuations in traffic demand, a load on a cell varies over time. However, it is not economically feasible to arrange a telecommunication network so that the network can always handle traffic demand.
Load balancing is one method that may be used to improve resource usage in a telecommunication network (e.g., a wireless or cellular network). Load balancing typically strives to offload traffic from an overloaded (or close to overloaded) cell to one or more other less loaded cells that may handle extra traffic. In the Third Generation Partnership Project (3GPP) standardization of Long Term Evolution (LTE) technology, load balancing is proposed that equalizes resource usage and enables base stations to exchange resource utilization percentages with each other over a direct interface.
However, current load balancing solutions typically assume some frequency planning so that two adjacent cells do not operate at the same frequency. Since the cells operate on different frequencies, a UE's connection that is prematurely transferred from a serving cell to a target cell may not cause any significant radio impairments to the serving cell. A successful transfer of a UE from a serving cell to a target cell may depend on whether a distance between the serving cell and the UE is too large to jeopardize a call or session for the transferred UE (e.g., due to a weak signal). In systems using single cell (1-cell) reuse (e.g., the 3GPP LTE standard), changing a cell affiliation for a UE will change the frequency interference situation for the moved UE as well as for other UEs.
In current systems, moving UEs from a serving cell to a target cell that is not a strongest cell may result in more resources being available for UEs remaining in the serving cell, and may result in less resources being available for existing UEs in the target cell. Furthermore, interference patterns will change for the UEs. For example, prior to the move, the moved UEs do not interfere with other UEs in the serving cell, but interfere with other cells. After the move, the moved UEs interfere with the UEs remaining in the serving cell, but do not interfere with UEs in the target cell. Higher interference levels in the cells may also result in a lower achievable bit rate for the UEs.
A shortcoming of the 3GPP LTE load balancing standard is the focus on balancing resource usage between cells. Such an approach fails to address user throughput for the UE, which is becoming increasingly important for data users. Other load balancing approaches often attempt to balance a number of users based on the assumption that all users (e.g., UEs) have the same service needs (e.g., a single voice session). High data peak rates by UEs may only be experienced during good transmission conditions and at times of few active users. In order to provide a trustworthy broadband service, it may be more important to provide as high a user throughput as possible for unfortunate users. For example, if a user (e.g., UE) receives six or nine megabits per second (Mbps) of data, user throughput may not make a noticeable difference for the user. However, if a user often experiences fifty kilobits per second (kbps) and, alternatively, almost never experiences below two-hundred and fifty kbps, the user throughput may significantly contribute to a user's experience. In other words, increasing the fairness among users may raise a performance of users that otherwise may underperform.